Toll-like receptors in Immunity and inflammation

Abstract

Toll-like receptors (TLRs) are critical components of innate immunity and serve as pattern recognition receptors (PRRs). These PRRs recognize different microbe or pathogen-associated molecular patterns (MAMPs or PAMPs) and death/danger-associated molecular patterns to initiate the pro-inflammatory immune reaction in response to foreign and internal dangers. PRRs, including TLRs, also connects innate immunity to adaptive immunity. Furthermore, TLRs expressed on both innate and adaptive (T and B cells) immune cells regulate their functions. TLRs were first discovered in the common fruit fly or Drosophila melanogaster as genes controlling dorso-ventral body patterning during embryonic development. Immunological and scientific advances have led to the discovery of different TLRs (extra and intracellular) with diverse functions. The present chapter introduces the role of TLRs in immunity and inflammation and their expansion to mammalian reproduction and embryonic development, maintenance of immune homeostasis, health, and disease, specifically neurological disorders, including neurodegeneration and cancers.